Which structure becomes cloudy in cataracts?

• A. Cornea
• B. Iris
• C. Lens
• D. Retina

Answer: (C)

Cataracts cause cloudiness of the lens. The lens is normally transparent, which allows light to pass through with minimal scattering so images can be focused on the retina. Its clarity depends on tightly packed crystallin proteins and the orderly arrangement of lens fibers. With aging or other stressors, these proteins denature and aggregate, and the lens fibers become disrupted, causing light to scatter and form opacities. This clouding reduces vision because the eye can’t transmit a clear image to the retina. The cornea, iris, and retina don’t develop the characteristic lens opacities seen in cataracts; clouding there would reflect other eye conditions (corneal edema or disease, iris changes, or retinal pathology).